1. The Field of the Invention
The present invention relates generally to centrifuge tubes. More particularly, it concerns a centrifuge tube having temporary liquid storage cavities formed upon a removable lid of the tube.
2. The Background Art
There is often a need in the practice of centrifugation to induce mixing of one or more reagents with a specimen contained in a centrifuge tube at a precise time. It is known to provide reagent-retaining structures, such as temporary storage cavities or ledges, on the inner side walls of a centrifuge tube. A precise amount of reagent is placed upon the retaining structure with a pipette tip or the like. The retaining structure prevents the reagent from mixing with the specimen in the bottom of the tube until centrifugal force is applied to the tube.
However, the prior art centrifuge tubes are characterized by a number of disadvantages. There is limited access to the reagent-retaining structures because of the narrow opening of the centrifuge tube. The limited access increases the difficulty involved in dispensing and placing the reagent properly. The reagent-retaining structures often occupy space in the opening or in the central portion of the centrifuge tube, which reduces the space available for unencumbered mixing action. Further, the prior art reagent-retaining structures are not able to retain the reagent if the centrifuge tube is inadvertently turned upside down.